CN113203931B - In-situ measurement system and method for CCD saturation signal after gamma ray irradiation - Google Patents

Abstract

The invention provides an in-situ measurement system and method for a CCD saturation signal after γ-ray irradiation, which can effectively reduce the complexity of the existing measurement system and the danger of experimenters when carrying out γ-ray irradiation experiments. , to improve the experimental efficiency; at the same time, the system and method can obtain the saturated signal parameters in a short time after irradiation is completed, and provide testing technical support for studying the total dose effect of CCD ⁶⁰ Coγ-ray irradiation. The in-situ measurement system includes a light source unit, a radiation source unit, a CCD irradiation unit, a signal processing unit and a host computer; the radiation source unit is used to induce ionization damage to the CCD irradiation unit; the light source unit is used to provide uniformity to the CCD irradiation unit The light source makes it reach a saturated working state; the signal processing unit is used to collect the image data of the CCD irradiation unit, and wirelessly transmit the image data to the host computer over a long distance; the host computer receives the image data and processes it to obtain a saturated signal change curve.

Description

In-situ measurement system and method for CCD saturation signal after γ-ray irradiation

technical field

The invention relates to the field of radiation effect testing, in particular to an in-situ measurement system and method of a charge-coupled device saturation signal after gamma ray irradiation.

Background technique

Charge coupled device (CCD) is a solid-state photoelectric conversion image sensor with MOS structure. It uses electric charge as a signal and forms a transfer barrier under the oxide layer through gate voltage. It is transferred to the output amplifier to output electrical signals, and has functions such as imaging, signal processing, and communication. Due to the advantages of low noise, light weight, wide dynamic range, stable operation and high quantum efficiency, CCDs are widely used in the fields of remote sensing, telemetry and space science detection. However, the CCD will be affected by ionization damage in the space radiation or nuclear radiation environment, which will produce a total dose effect, resulting in the degradation of the performance of the CCD, and even the function failure in severe cases, which in turn affects the performance and operating life of the on-orbit aerospace system.

High-energy electrons, protons, etc. in the space environment will induce ionization damage to the CCD, resulting in a decrease in the saturation signal of the CCD, thus affecting the performance of the CCD. Therefore, the saturation signal is an important radiation-sensitive parameter for evaluating the anti-irradiation damage performance of the CCD. At present, a large number of theoretical calculations and scientific practices have shown that ⁶⁰ Coγ source is the most ideal radiation source for conducting ground simulation experiments on the effect of total ionizing dose of components. When evaluating and verifying the radiation resistance performance of CCDs on the ground, ⁶⁰ Coγ rays are usually used to study the total dose effect of CCDs. At present, due to the limited transmission distance of common transmission methods such as USB and IEEE1394, the extraction of saturated signal parameters in most ⁶⁰ Coγ-ray irradiation experiments is based on displacement measurement, that is, after the radiation dose accumulates at a certain dose point, the source needs to be lowered to take out the device. After the test is completed, it is put in again, which brings great inconvenience to the irradiation experiment and cannot obtain the variation law of the saturation signal in a short time after the irradiation is completed.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an in-situ measurement system and method of CCD saturation signal after γ-ray irradiation, which can effectively reduce the tediousness of the existing measurement system and the experimental personnel when carrying out γ-ray irradiation experiments. At the same time, the system and method can obtain the saturation signal parameters in a short time after irradiation is completed, and provide testing technical support for studying the total dose effect of CCD ⁶⁰ Coγ-ray irradiation.

To achieve the above object, the present invention adopts the following technical solutions:

An in-situ measurement system for a CCD saturation signal after gamma ray irradiation, comprising a light source unit, a radiation source unit, a CCD irradiation unit, a signal processing unit and a host computer; the radiation source unit includes a radiation source and a radiation source lifting device, The radiation source is used to induce ionization damage to the CCD irradiation unit, and the radiation source lifting device is connected to the radiation source to control the position of the radiation source; the light source unit includes a light source, a light source lifting device and a light source shielding box, so The light source is used to provide a uniform light source for the CCD irradiation unit to make it reach a saturated working state; the light source lifting device is connected with the light source to control the position of the light source, and the light source shielding box is arranged below the light source. The light source is located in the light source shielding box to avoid the influence of the radiation source on the light source; the CCD irradiation unit includes a CCD sensor, and the emitted light of the light source and the γ-ray of the radiation source are vertically irradiated on the CCD sensor; the signal processing unit includes A CCD driving circuit module, an A/D conversion module, an FPGA main control module, a wireless transmission module and a power supply module; the CCD driving circuit module is respectively connected with the CCD sensor and the FPGA main control module, and drives the TTL timing generated by the FPGA main control module The signal is converted into a driving signal that meets the voltage requirements of the CCD sensor, the CCD sensor completes image acquisition under the driving of the driving signal, and outputs an image analog signal; the A/D conversion module is respectively connected with the CCD sensor and the FPGA main control module , perform pre-filtering, signal amplification, dark level clamping, denoising correlated double sampling processing on the image analog signal, and convert the image analog signal into a digital signal; the FPGA main control module is used to generate a CCD The TTL timing drive signal of the normal operation of the sensor provides the clamping and sample/hold pulse signals required by the A/D conversion module, and uses the built-in storage to cache image data; the wireless transmission module is connected to the FPGA main control module, and the cache is stored in the FPGA. The image data of the FPGA main control module is wirelessly transmitted to the host computer over a long distance; the host computer receives and stores the image data transmitted by the wireless transmission module and processes it to obtain the change curve of the saturation signal; the power module is respectively connected with the CCD sensor. , FPGA main control module, CCD drive circuit module, A/D conversion module, wireless transmission module are connected to provide stable voltage for each module.

Further, the signal processing unit is arranged in the signal unit shielding box, and the signal unit shielding box is used to shield the influence of the radiation source on the signal processing unit, so that the signal processing unit is arranged in the irradiation room to reduce the CCD irradiation unit and the signal. The transmission distance of the processing unit ensures the stable operation of the system.

Further, the CCD sensor is connected with the power supply module, the A/D conversion module and the CCD driving circuit module through a DuPont line.

Further, the wireless transmission module includes a sending end and a receiving end, the sending end is mainly composed of a single-chip STM32 and a 433MHz wireless sending unit, and the receiving end is mainly composed of a wireless receiving unit and a USB to TTL module, and is realized through the USB interface. machine wireless communication.

Further, the A/D conversion module includes an analog signal preprocessing circuit and an analog-to-digital conversion circuit, and the analog signal preprocessing circuit performs pre-filtering, signal amplification, black level clamping, Denoising correlated double sampling processing, the analog-to-digital conversion circuit converts the image analog signal into a digital signal.

Further, the analog signal preprocessing circuit includes a constant current drive circuit and a filter amplifying circuit, and the FPGA main control module includes a field logic editable array and a FLASH storage circuit.

Further, the host computer includes a data receiving host computer and an external remote control host computer, and the data receiving host computer receives the image data sent by the wireless transmission module receiving end through the USB interface, and transmits the image data to the external remote control through the network cable. The host computer is controlled, and the external remote control host computer receives and saves the image data, and processes the image data to obtain the variation curve of the saturated signal, and obtain the variation rule of the saturated output signal before and after CCD irradiation.

Further, the rays emitted by the radiation source are ⁶⁰ Coγ rays, the wireless receiving unit adopts XL08-232AP1 with an operating frequency of 433MHz, and the USB to TTL module adopts CH340 conversion module.

At the same time, the present invention also provides a measurement method based on the in-situ measurement system of the CCD saturation signal after the above-mentioned γ-ray irradiation, the method comprising the following steps:

Step 1: Wipe the photosensitive surface of the CCD sensor clean and place it at the irradiation point, so that the direction of the γ-ray beam of the radiation source is perpendicular to the photosensitive surface of the CCD sensor;

Step 2: Build a liftable light source unit in the irradiation room, so that the light emitted from the light source can be vertically irradiated to the photosensitive surface of the CCD sensor, so as to ensure that the CCD sensor works under uniform lighting conditions during the test;

Step 3: Control the temperature of the experimental environment at the set temperature, and control the influence of the temperature on the saturation signal;

Step 4: Connect the signal processing unit to the CCD sensor, and place the signal processing unit in the shielding box of the signal unit to avoid being affected by irradiation;

Step 5. Connect the host computer to the wireless transmission module, and then turn on the light source;

Step 6: The upper computer sends a collection instruction and adjusts the intensity of the light source, completes the collection of the saturation signal of the CCD sensor before irradiation, and saves the data;

Step 7. Repeat step 6 for several times to obtain the saturated signal data before the CCD sensor irradiation;

Step 8. In the saturated signal data obtained in step 7, remove the extreme values of all pixels in each frame of data and then calculate the average value. According to the processed saturated signal data, determine whether the CCD sensor is working stably and is in a saturated state. When the CCD sensor is in a saturated state, After the work is stable and in a saturated state, turn off the light source, set the light source in the light source shielding box, and record the intensity of the light source;

Step 9. The radiation source is turned on, and the irradiation starts. After the irradiation is completed, the radiation source is lifted to a certain position;

Step 10. The host computer sends a collection instruction, the CCD sensor collects data, and judges whether the CCD sensor is invalid according to the collected data. If the data collected by the CCD sensor is valid, the next step is performed;

Step 11: Raise the light source so that the light emitted from the light source can be vertically irradiated to the photosensitive surface of the CCD sensor, turn on the light source with the same intensity before irradiation, and at a certain interval, the host computer sends a collection instruction to collect the CCD sensor irradiation for multiple times. After the saturated signal data, and save the saturated signal data;

Step 12: Calculate the average value of pixels in each frame of the data collected in step 11, and then remove the extreme values in multiple sets of data to obtain the variation curve of the saturated signal after irradiation, and compare the data with the saturated signal before irradiation. The data were compared, and the influence of irradiation on the saturated output signal of the CCD sensor was analyzed.

Further, in step 3, the set temperature is 25 degrees; in step 7, repeat step 6 for 20 times; in step 11, the upper computer sends a collection instruction, a total of 100 times to collect the saturated signal data irradiated by the CCD sensor, and Save the saturated signal data.

Compared with the prior art, the system and method of the present invention have the following significant advantages:

1. The system and method of the present invention can effectively avoid the problem of tediousness of the existing measurement system when carrying out γ-ray irradiation experiments, thereby improving the experimental efficiency, and can obtain the saturation signal parameters in a short time after the irradiation is completed. The total dose effect of γ-ray irradiation of CCD provides technical support for testing.

2. The system of the present invention adopts the sub-motherboard design method in which the CCD irradiation unit and the signal processing unit are separated. During the experiment, the signal processing unit is set in the signal unit shielding box to reduce the influence of the radiation source on the signal processing unit and ensure the stability of the system. run.

3. The system and method of the present invention realizes communication with the host computer through wireless transmission, simplifies the system connection mode, can avoid system instability caused by long-term connection, and can make the host computer receiving the data in a safe position to avoid irradiation And through the remote control function between the host computers, the experimenter can remotely operate the test system in a safe environment, reducing the frequency of the experimenter entering the irradiation room, effectively reducing the risk of the experimenter, and solving the problem of ⁶⁰ Coγ-ray radiation. According to the problem of CCD in-situ measurement after the experiment.

Description of drawings

Fig. 1 is the schematic diagram of the in-situ measurement system of CCD saturation signal after γ-ray irradiation of the present invention;

Fig. 2 is the composition schematic diagram of the signal processing unit of the present invention;

FIG. 3 is a flow chart of the in-situ measurement method of the CCD saturation signal after γ-ray irradiation according to the present invention.

Reference signs: 1-light source, 2-light source lifting device, 3-light source shielding box, 4-radiation source, 5-radiation source lifting device, 6-CCD sensor, 7-irradiation plate, 8-DuPont line, 9- Signal unit shielding box, 10-signal processing unit, 11-data receiving host computer, 12-network cable, 13-external remote control host computer.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

The invention provides an in-situ measurement system and method for a CCD saturation signal after ⁶⁰ Coγ-ray irradiation, which can effectively reduce the tediousness of the existing measurement system and the labor of experimenters when carrying out ⁶⁰ COγ-ray irradiation experiments. Dangerous, so as to improve the experimental efficiency, and can obtain the saturated signal parameters in a short period of time after the irradiation is completed; at the same time, the system adopts the sub-mother board design scheme that the CCD irradiation unit and the signal processing unit are separated, which can effectively reduce the radiation source. The impact on the signal processing unit ensures the stable operation of the system; in addition, the system realizes long-distance wireless transmission with the host computer through wireless transmission, and the experimenter can remotely control the test system in a safe environment, reducing the experimenter's access to radiation The frequency of the chamber is effectively reduced, and the risk of the experimenter is effectively reduced, and the problem of CCD in-situ measurement after the ⁶⁰ Coγ-ray irradiation experiment is solved.

As shown in FIG. 1 , the in-situ measurement system of the CCD saturation signal after γ-ray irradiation provided by the present invention includes a light source unit, a radiation source unit, a CCD irradiation unit, a signal processing unit 10 and a light source unit arranged in the irradiation chamber, a signal processing unit 10 and a According to the outdoor host computer. The radiation source unit includes a radiation source 4 and a radiation source lifting device 5. The radiation source 4 is used to ^induce ionizing damage to the CCD irradiation unit. It is used to control the position of the radiation source 4 so that the radiation source 4 can move up and down. The light source unit includes a light source 1, a light source lifting device 2 and a light source shielding box 3. The light source 1 provides a stable and uniform light source 1 for the CCD irradiation unit to make it reach a saturated working state; the light source lifting device 2 is used to control the position of the light source 1, so that the light source 1 can move up and down, the light source shielding box 3 is arranged below the light source 1, and the light source 1 is lowered into the light source shielding box 3 when irradiating, so as to avoid the radiation source 4 from affecting the light source 1. The CCD irradiation unit includes a CCD sensor 6. The CCD sensor 6 can be installed on the irradiation plate 7. The light source 1, the radiation source 4 and the CCD sensor 6 maintain the same horizontal position, so that the outgoing light of the light source 1 and the γ-ray of the radiation source 4 The CCD sensor 6 is irradiated vertically.

As shown in FIG. 2, the signal processing unit 10 includes a CCD driving circuit module, an A/D conversion module, an FPGA main control module, a wireless transmission module and a power supply module; the power supply module is respectively connected with the CCD sensor 6, the FPGA main control module, and the CCD driving circuit. The module, A/D conversion module and wireless transmission module are connected to provide stable voltage for each module of the system. The CCD driving circuit module is respectively connected with the FPGA main control module and the CCD sensor 6, and converts the TTL timing driving signal generated by the FPGA main control module into a driving signal that meets the voltage requirements of the CCD sensor 6; the CCD sensor 6 is driven by the driving signal to complete the image. Collect and output the image analog signal; the A/D conversion module is connected to the CCD sensor 6 and the FPGA main control module, respectively, to perform pre-filtering, signal amplification, and dark electricity on the input original CCD analog signal (ie, image analog signal). Flat clamp, de-noise correlated double sampling processing, and convert the original analog signal (ie image analog signal) output by the CCD into a digital signal through the A/D converter and transmit it to the FPGA main control module; A/D conversion module It includes an analog signal preprocessing circuit and an analog-to-digital conversion circuit; the analog signal preprocessing circuit includes a constant current drive circuit and a filter amplifying circuit, which performs pre-filtering, signal amplification, black level clamping, and noise removal for the input image analog signal. Correlated double sampling processing, the analog-to-digital conversion circuit converts the image analog signal into a digital signal. The FPGA main control module is the core of the system, including the field logic editable array and FLASH storage circuit, which is responsible for generating the TTL timing drive signal for the normal operation of the CCD sensor 6, and providing the clamping and sampling required for the A/D processing of the original analog signal /Maintain the pulse signal, while using the built-in storage resources to buffer the image data and transmit it to the wireless transmission module.

The wireless transmission module of the invention includes two parts: a sending end and a receiving end. The sending end is mainly composed of a control unit single chip STM32 and a 433MHz wireless sending unit. The receiving end is mainly composed of a wireless receiving unit and a USB to TTL module. The sending end and the FPGA main control module Connected, the image data cached in the FPGA main control module is wirelessly and long-distance transmitted to the receiving end, the receiving end completes the data format conversion through the USB to TTL module, and transmits the received data to the data receiving host computer 11 through the USB interface; data; The receiving host computer 11 is connected with the receiving end of the wireless transmission module through USB. The external remote control host computer 13 is connected to the data receiving host computer 11 through the network cable 12. The external remote control host computer 13 receives and saves the image data, and processes the image data to obtain the change curve of the saturation signal, and obtain the saturation output signal change before and after CCD irradiation. law.

When the irradiation experiment is carried out, the signal processing unit 10 of the present invention is arranged in the signal unit shielding box 9, and the signal unit shielding box 9 is used to shield the influence of the radiation source 4 on the signal processing unit 10, so that the signal processing unit 10 is arranged in the irradiation room. , reducing the transmission distance between the CCD irradiation unit and the signal processing unit 10 to ensure the stable operation of the system. The CCD sensor 6 is connected to the power supply module, the A/D conversion module and the CCD driving circuit module through the DuPont line 8. Driven by the TTL timing signal provided by the FPGA main control module, the driving timing signal that meets the CCD voltage requirements is converted by the level driver. , the original analog output of the CCD image signal.

As shown in FIG. 2, in the signal processing unit 10 of the present invention, the CCD driving timing and the clamping and sampling/holding pulse signals required for A/D conversion processing are implemented by the FPGA main control module through Verilog hardware description language programming, and the CCD driving The timing takes the internal system clock of the FPGA main control module as the reference clock, and uses the counter to divide the frequency to obtain the driving signals that meet the timing requirements; the A/D conversion module requires the FPGA main control module to provide correct register assignments and sampling clock signals that meet the timing requirements. In order to ensure its normal operation, the internal registers are set by the FPGA through the serial interface to realize the setting of VGA gain, black level correction, input clock polarity and other functions. The FPGA internal system clock is used as the reference clock, and the counter is used to divide the The wireless transmission module realizes data mutual transmission through serial port, and sets the parameters such as baud rate, data bit, stop bit and parity of the sending end and the receiving end to be the same, and agrees on the data frame protocol. to communicate correctly.

In the in-situ measurement system of the CCD saturation signal after ⁶⁰ COγ-ray irradiation of the present invention, the TTL timing sequence generated by the FPGA main control module is passed through the CCD driving circuit module to obtain a driving signal that meets the CCD voltage requirements, and the CCD sensor 6 outputs under the action of the driving signal. For the original analog signal, the A/D conversion module performs filtering, denoising and analog-to-digital conversion on the original analog signal, and the obtained digital signal is buffered in the internal storage resources of the FPGA, and then controlled by the STM32 single-chip microcomputer STM32 The sending end of the wireless transmission unit sends to the receiving end. The receiving end completes the data format conversion through the USB to TTL module, and transmits the received data to the host computer through the USB interface to obtain the saturated signal parameters; the wireless transmission transceiver unit can use the XL08-232AP1 with an operating frequency of 433MHz, and the USB to TTL specific can use CH340 conversion module.

Based on the above system, the present invention provides an in-situ measurement method for a CCD saturation signal after γ-ray irradiation. In this method, after each cumulative dose point irradiation is completed, the radiation source lifting device 5 performs a source lowering operation, and the light source The lifting device 2 lifts the light source 1 from the light source shielding box 3 to the horizontal irradiation point, turns on the light source 1 to adjust to the saturation intensity before irradiation, collects the saturation signal of the CCD sensor 6, and obtains the variation law of the saturation signal in a short time.

As shown in FIG. 3 , the in-situ measurement method of the CCD saturation signal after radiation irradiation provided by the present invention specifically includes the following steps:

Step 1: Wipe the photosensitive surface of the CCD sensor 6 clean and place it at the irradiation point, so that the direction of the γ-ray beam of the radiation source 4 is perpendicular to the photosensitive surface of the CCD sensor 6;

Step 2: Build a liftable light source 1 system in the irradiation room. After the building is completed, turn on the light source 1, so that the horizontal irradiation point of the light source 1 can vertically illuminate the photosensitive surface of the CCD sensor 6, so as to ensure that the CCD sensor 6 works under uniform illumination during the test. condition;

Step 3: Control the temperature of the experimental environment at about 25°C to control the influence of the temperature on the saturation signal;

Step 4: Connect the signal processing unit 10 to the CCD sensor 6, and place the signal processing unit 10 in the signal unit shielding box to avoid the influence of irradiation on it;

Step 5. Connect the data receiving host computer 11 to the receiving end of the wireless transmission module, and place it in the safety aisle of the irradiation room to avoid the impact of irradiation on the host computer. Use the network cable 12 to receive the irradiation room data from the host computer 11 and the outside The remote control host computer 13 is connected to perform remote control on the data receiving host computer 11 in the irradiation room, and the power supply module is turned on to supply power;

Step 6: Send the acquisition instruction through the external remote control host computer 13, adjust the intensity of the light source 1 at the same time, complete the acquisition of the saturation signal of the CCD sensor before irradiation, and save the data;

Step 7: Repeat step 6 for 20 times to complete the measurement of the saturation signal before irradiation, and obtain the saturation signal data of the CCD sensor 6 before irradiation;

Step 8. In the saturated signal data obtained in Step 7, remove the extreme values of all pixels in each frame of data, and then calculate the average value. According to the processed saturated signal data, determine whether the CCD is working stably and is in a saturated state. When the CCD is working stably And after being in a saturated state, turn off the light source 1, drop the light source 1 into the light source shielding box 3, and record the intensity of the light source 1;

Step 9, the radiation source 4 is turned on, and the irradiation is started. After the irradiation is completed, the radiation source lifting device 5 performs a source lowering operation to lower the radiation source 4 to a certain position;

Step ten, the external remote control host computer 13 sends the acquisition instruction, the signal processing unit 10 completes the data acquisition, and judges whether the CCD sensor 6 is invalid according to the collected data, if the CCD sensor 6 collects data valid, execute the next step;

Step 11. Turn on the light source lifting device 2, make the light source 1 rise to the horizontal irradiation point, turn on the light source 1 with the same intensity before irradiation, and at a certain interval, the external remote control host computer 13 sends a start command to collect the 6 radiation of the CCD sensor. Saturated signal data after exposure, collected 100 times in total, and saved the saturated signal data;

Step 12: Calculate the average value of pixels in each frame for the data collected in step 11, and then remove the extreme values in the 100 groups of data to obtain the change curve of the saturated signal, compare it with the pre-irradiation data in step 7, and analyze the irradiation. Influence on the saturated output signal of the CCD sensor 6 .

Claims (10)

1. An in-situ measurement system of a CCD saturation signal after gamma ray irradiation is characterized in that: the device comprises a light source unit, a radiation source unit, a CCD irradiation unit, a signal processing unit (10) and an upper computer;

the radiation source unit comprises a radiation source (4) and a radiation source lifting device (5), the radiation source (4) is used for inducing the CCD irradiation unit to generate ionization damage, and the radiation source lifting device (5) is connected with the radiation source (4) and used for controlling the position of the radiation source (4);

the light source unit comprises a light source (1), a light source lifting device (2) and a light source shielding box (3), wherein the light source (1) is used for providing a uniform light source for the CCD irradiation unit to enable the CCD irradiation unit to reach a saturated working state; the light source lifting device (2) is connected with the light source (1) and used for controlling the position of the light source (1), the light source shielding box (3) is arranged below the light source (1), the light source (1) is positioned in the light source shielding box (3) during irradiation, and the influence of the radiation source (4) on the light source (1) is avoided;

the CCD irradiation unit comprises a CCD sensor (6), and emergent light of the light source (1) and gamma rays of the radiation source (4) are vertically irradiated on the CCD sensor (6);

the signal processing unit (10) comprises a CCD driving circuit module, an A/D conversion module, an FPGA main control module, a wireless transmission module and a power supply module; the CCD driving circuit module is respectively connected with the CCD sensor (6) and the FPGA main control module, TTL time sequence driving signals generated by the FPGA main control module are converted into driving signals meeting the voltage requirements of the CCD sensor (6), and the CCD sensor (6) completes image acquisition under the driving of the driving signals and outputs image analog quantity signals; the A/D conversion module is respectively connected with the CCD sensor (6) and the FPGA main control module, carries out pre-stage filtering, signal amplification, dark level clamping and noise removal related double sampling processing on the image analog quantity signal, and converts the image analog quantity signal into a digital quantity signal; the FPGA main control module is used for generating TTL time sequence driving signals for normal work of the CCD sensor (6), providing clamping and sampling/holding pulse signals required by the A/D conversion module, and caching image data by utilizing built-in storage; the wireless transmission module is connected with the FPGA main control module and wirelessly transmits the image data cached in the FPGA main control module to an upper computer in a long distance;

the upper computer receives and stores the image data transmitted by the wireless transmission module and processes the image data to obtain a change curve of the saturation signal; the power supply module is respectively connected with the CCD sensor (6), the FPGA main control module, the CCD drive circuit module, the A/D conversion module and the wireless transmission module, and provides stable voltage for each module.

2. The system for in-situ measurement of a saturation signal of a gamma-irradiated CCD according to claim 1, wherein: the signal processing unit (10) is arranged in the signal unit shielding box (9), and the signal unit shielding box (9) is used for shielding the influence of the radiation source (4) on the signal processing unit (10), so that the signal processing unit (10) is arranged in the irradiation chamber, the transmission distance between the CCD irradiation unit and the signal processing unit (10) is reduced, and the stable operation of the system is ensured.

3. The system for in-situ measurement of a saturation signal of a gamma-irradiated CCD according to claim 2, wherein: and the CCD sensor (6) is connected with the power supply module, the A/D conversion module and the CCD driving circuit module through a DuPont wire (8).

4. The system for in-situ measurement of a CCD saturation signal after gamma ray irradiation according to claim 1, 2 or 3, wherein: the wireless transmission module comprises a sending end and a receiving end, the sending end mainly comprises a single chip microcomputer STM32 and a 433MHz wireless sending unit, the receiving end mainly comprises a wireless receiving unit and a USB-to-TTL module, and the receiving end realizes wireless communication with an upper computer through a USB interface.

5. The system for in-situ measurement of a CCD saturation signal after gamma irradiation according to claim 4, wherein: the A/D conversion module comprises an analog signal preprocessing circuit and an analog-to-digital conversion circuit, the analog signal preprocessing circuit carries out pre-stage filtering, signal amplification, dark level clamping and noise removal related double sampling processing on an input image analog quantity signal, and the analog-to-digital conversion circuit converts the image analog quantity signal into a digital quantity signal.

6. The system for in-situ measurement of a CCD saturation signal after gamma irradiation according to claim 5, wherein: the analog signal preprocessing circuit comprises a constant current driving circuit and a filtering amplifying circuit, and the FPGA main control module comprises a field logic editable array and a FLASH storage circuit.

7. The system for in-situ measurement of a CCD saturation signal after gamma irradiation according to claim 6, wherein: the upper computer comprises a data receiving upper computer (11) and an external remote control upper computer (13), the data receiving upper computer (11) receives image data sent by a wireless transmission module receiving end through a USB interface and transmits the image data to the external remote control upper computer (13) through a network cable (12), and the external remote control upper computer (13) receives and stores the image data and processes the image data to obtain a change curve of a saturation signal and obtain a change rule of a saturation output signal before and after the CCD sensor is irradiated.

8. The system for in-situ measurement of a CCD saturation signal after gamma irradiation according to claim 7, wherein: the ray emitted by the radiation source (4) is⁶⁰Co gamma ray, XL08-232AP1 with the working frequency of 433MHz is adopted by the wireless receiving unit, and a CH340 conversion module is adopted by the USB-to-TTL module.

9. A measurement method based on an in-situ measurement system of a CCD saturation signal after gamma ray irradiation according to any one of claims 1 to 8, comprising the steps of:

wiping a photosensitive surface of a CCD sensor and placing the photosensitive surface at an irradiation point to ensure that the direction of a gamma ray beam of a radiation source is vertical to the photosensitive surface of the CCD sensor;

step two, a liftable light source unit is built in an irradiation chamber, so that emergent light of a light source can vertically irradiate a photosensitive surface of the CCD sensor, and the CCD sensor is ensured to work under the condition of uniform illumination during testing;

step three, controlling the temperature of the experimental environment at a set temperature, and controlling the influence of the temperature on the saturation signal;

fourthly, connecting the signal processing unit with the CCD sensor, and placing the signal processing unit in a signal unit shielding box to avoid the influence of irradiation on the signal processing unit;

connecting the upper computer with the wireless transmission module, and then turning on a light source;

step six, the upper computer sends an acquisition instruction and adjusts the intensity of a light source, the acquisition of a saturation signal of the CCD sensor before irradiation is completed, and data are stored;

step seven, repeating the step six for multiple times to obtain saturated signal data before the irradiation of the CCD sensor;

step eight, in the saturated signal data obtained in the step seven, eliminating extreme values of all pixels in each frame of data, then calculating an average value, judging whether the CCD sensor works stably and is in a saturated state according to the processed saturated signal data, and when the CCD sensor works stably and is in the saturated state, turning off the light source, arranging the light source in a light source shielding box, and recording the intensity of the light source;

step nine, starting a radiation source, starting irradiation, and lifting the radiation source to a certain position after the irradiation is finished;

step ten, the upper computer sends an acquisition instruction, the CCD sensor carries out data acquisition, whether the CCD sensor fails or not is judged according to the acquired data, and if the data acquired by the CCD sensor is effective, the next step is executed;

step eleven, raising a light source to enable emergent light of the light source to vertically irradiate a photosensitive surface of the CCD sensor, starting the light source with the same intensity before irradiation, sending a collection instruction by the upper computer at intervals of a certain time, collecting saturated signal data after the irradiation of the CCD sensor for multiple times, and storing the saturated signal data;

step twelve, calculating the average value of each frame of pixels of the data collected in the step eleven, then eliminating the extreme values in multiple groups of data to obtain the variation curve of the irradiated saturated signal, comparing the data with the saturated signal data before irradiation, and analyzing the influence of irradiation on the saturated output signal of the CCD sensor.

10. The measurement method according to claim 9, characterized in that: in the third step, the temperature is set to be 25 ℃; in the seventh step, the sixth step is repeated for 20 times; and step eleven, the upper computer sends an acquisition instruction, acquires the saturated signal data after the irradiation of the CCD sensor for 100 times, and stores the saturated signal data.

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